Adding Laundry Room Drain to Kitchen Drain

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by lukus, May 19, 2008.

  1. lukus

    lukus New Member

    Sep 21, 2007
    I want to move my laundry room from the basement to the mud room that is next to the kitchen on the main floor.
    - The mud room currently has a drain that measures 1-3/8" OD and is metal (maybe brass, but it's painted) - so probably 1-1/4" drain. This drain does not connect to the 2" kitchen drain. It has a sink that will be replaced.
    - The kitchen has a 2" drain & vent. The drain runs down (vertical) about 6 feet and then about 10 feet horizontal to the main 4" stack. The kitchen sink is the only thing currently connected to the drain - no dishwasher or food disposer. The 2" drain is also on the common wall between the mud room and the kitchen.

    What i want is to move the washer and dryer to the mud room but i don't think that the 1-1/4" drain is sufficient for the sink & washer. I'll have the washer drain into the sink, either directly or to a vertical pipe connected just above the p-trap of the sink.

    So what I was thinking of doing was connecting the mud/laundry room sink to the 2" kitchen drain.
    - Is this possible?
    - And if so then what about if i later want to add a dishwasher?
  2. jimbo

    jimbo Plumber

    Aug 31, 2004
    San Diego, CA
    The washer does need 2", and depending on where you are, they may not allow the washer drain to share a pipe with another sink. Would it work.....yes. Make sure your venting is up to snuff.
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  4. DuWayne

    DuWayne New Member

    May 19, 2008
    If you are concerned about inspections then you really need to find out the relevant local code. It will work just fine to combine them, but it may not be allowed in your area - it's not in mine. If your not concerned about selling your house or having building inspectors in, then use the sink drain and don't worry about it.

    The dishwasher isn't going to be a problem either, though you might get some backing into the sink if you run the dishwasher and washing machine at the same time (actually why it's code in many places). It's doubtful that it would back up very far unless you have really bad drains.

    If you have access to the 1 1/4" mud room drain you might track it to where it connects into a larger pipe. It might be possible to run a 2" from there which would be the ideal. I would suspect that the same trunk line drains the kitchen and mud room.
  5. lukus

    lukus New Member

    Sep 21, 2007
    The 1-1/4" runs below the basement floor. The 2" connects to the 4" stack about a foot above the basement floor. I actually suspect that the 1-1/4" drain connects to the storm drain. I know that one of the floor drains already connects to the storm drain. In this part of the city (Toronto, Canada), the (storm & sanitary) sewers are combined. The sanitary drain (sewer) runs along the centre of the basement floor. The storm drain runs just outside the house along the footing.
    Last edited: May 21, 2008
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